| OLD | NEW |
| 1 // Copyright 2013 The Chromium Authors. All rights reserved. | 1 // Copyright 2013 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ | 5 #ifndef CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ |
| 6 #define CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ | 6 #define CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ |
| 7 | 7 |
| 8 #include "base/basictypes.h" | 8 #include <stdint.h> |
| 9 | 9 |
| 10 // A wrapper around a memory buffer that allows circular read and write with a | 10 // A wrapper around a memory buffer that allows circular read and write with a |
| 11 // selectable wrapping position. Buffer layout (after wrap; H is header): | 11 // selectable wrapping position. Buffer layout (after wrap; H is header): |
| 12 // ----------------------------------------------------------- | 12 // ----------------------------------------------------------- |
| 13 // | H | Beginning | End | Middle | | 13 // | H | Beginning | End | Middle | |
| 14 // ----------------------------------------------------------- | 14 // ----------------------------------------------------------- |
| 15 // ^---- Non-wrapping -----^ ^--------- Wrapping ----------^ | 15 // ^---- Non-wrapping -----^ ^--------- Wrapping ----------^ |
| 16 // The non-wrapping part is never overwritten. The wrapping part will be | 16 // The non-wrapping part is never overwritten. The wrapping part will be |
| 17 // circular. The very first part is the header (see the BufferData struct | 17 // circular. The very first part is the header (see the BufferData struct |
| 18 // below). It consists of the following information: | 18 // below). It consists of the following information: |
| 19 // - Length written to the buffer (not including header). | 19 // - Length written to the buffer (not including header). |
| 20 // - Wrapping position. | 20 // - Wrapping position. |
| 21 // - End position of buffer. (If the last byte is at x, this will be x + 1.) | 21 // - End position of buffer. (If the last byte is at x, this will be x + 1.) |
| 22 // Users of wrappers around the same underlying buffer must ensure that writing | 22 // Users of wrappers around the same underlying buffer must ensure that writing |
| 23 // is finished before reading is started. | 23 // is finished before reading is started. |
| 24 class PartialCircularBuffer { | 24 class PartialCircularBuffer { |
| 25 public: | 25 public: |
| 26 // Use for reading. |buffer_size| is in bytes and must be larger than the | 26 // Use for reading. |buffer_size| is in bytes and must be larger than the |
| 27 // header size (see above). | 27 // header size (see above). |
| 28 PartialCircularBuffer(void* buffer, uint32 buffer_size); | 28 PartialCircularBuffer(void* buffer, uint32_t buffer_size); |
| 29 | 29 |
| 30 // Use for writing. |buffer_size| is in bytes and must be larger than the | 30 // Use for writing. |buffer_size| is in bytes and must be larger than the |
| 31 // header size (see above). If |append| is true, the header data is not reset | 31 // header size (see above). If |append| is true, the header data is not reset |
| 32 // and writing will continue were left off, |wrap_position| is then ignored. | 32 // and writing will continue were left off, |wrap_position| is then ignored. |
| 33 PartialCircularBuffer(void* buffer, | 33 PartialCircularBuffer(void* buffer, |
| 34 uint32 buffer_size, | 34 uint32_t buffer_size, |
| 35 uint32 wrap_position, | 35 uint32_t wrap_position, |
| 36 bool append); | 36 bool append); |
| 37 | 37 |
| 38 uint32 Read(void* buffer, uint32 buffer_size); | 38 uint32_t Read(void* buffer, uint32_t buffer_size); |
| 39 void Write(const void* buffer, uint32 buffer_size); | 39 void Write(const void* buffer, uint32_t buffer_size); |
| 40 | 40 |
| 41 private: | 41 private: |
| 42 friend class PartialCircularBufferTest; | 42 friend class PartialCircularBufferTest; |
| 43 | 43 |
| 44 #pragma pack(push) | 44 #pragma pack(push) |
| 45 #pragma pack(4) | 45 #pragma pack(4) |
| 46 struct BufferData { | 46 struct BufferData { |
| 47 uint32 total_written; | 47 uint32_t total_written; |
| 48 uint32 wrap_position; | 48 uint32_t wrap_position; |
| 49 uint32 end_position; | 49 uint32_t end_position; |
| 50 uint8 data[1]; | 50 uint8_t data[1]; |
| 51 }; | 51 }; |
| 52 #pragma pack(pop) | 52 #pragma pack(pop) |
| 53 | 53 |
| 54 void DoWrite(const uint8* input, uint32 input_size); | 54 void DoWrite(const uint8_t* input, uint32_t input_size); |
| 55 | 55 |
| 56 // Used for reading and writing. | 56 // Used for reading and writing. |
| 57 BufferData* buffer_data_; | 57 BufferData* buffer_data_; |
| 58 uint32 memory_buffer_size_; | 58 uint32_t memory_buffer_size_; |
| 59 uint32 data_size_; | 59 uint32_t data_size_; |
| 60 uint32 position_; | 60 uint32_t position_; |
| 61 | 61 |
| 62 // Used for reading. | 62 // Used for reading. |
| 63 uint32 total_read_; | 63 uint32_t total_read_; |
| 64 }; | 64 }; |
| 65 | 65 |
| 66 #endif // CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ | 66 #endif // CHROME_COMMON_PARTIAL_CIRCULAR_BUFFER_H_ |
| OLD | NEW |